This invention relates to the analysis of fluids in a fluid process stream, such as implemented by petrochemical plants, refineries, gas separation plants, etc., and in particular to an in-stream sample collection and conditioning system which is easier to implement and maintain, more cost effective, and more reliable than existing systems.
The preferred embodiment of the present system contemplates a modular system adaptable to a variety of diverse configurations and criteria, the system having incorporated therein a base piece formed of interconnecting modular base members, the base piece having fluid passageways formed therein to provide fluid flow between the adjacent base member(s).
Situated adjacent to each of the modular base members forming the base piece are modular conditioning components, each selected from a field of diverse conditioning types and configurations, and adapted for the contemplated use, the system dispensing with the necessity of tubes, pipes, and traditional fittings. The present system as a whole provides a wholly new and unprecedented system for custom building fluid stream sampling and conditioning systems with heretofore unavailable xe2x80x9coff-the-shelfxe2x80x9d components.
The present invention further contemplates a unique and useful system for joining the various modular components forming the present system, in a manner which provides redundant leak resistance, flexibility in providing various conditioning configurations, and adaptability to diverse existing sampling stream interfaces.
Lastly, the preferred embodiment of the present invention contemplates a highly precise, low tolerance juxtaposition of the various components forming the present system, utilizing an extremely thin sheet formed membrane/gasket member, implemented in such a manner as to provide high thermocycling characteristics as well as high pressure tolerance, coupled with a low failure/leakage rate.
While the prior art has contemplated various and diverse systems for sampling and/or conditioning fluids in a process stream, said prior art systems tended to require a xe2x80x9ccustomxe2x80x9d configuration for each site, entailing an expensive and time-consuming design, fabrication, and installation.
Processes as implemented in, for example, petrochemical plants, refineries, gas separation plants, etc. frequently require xe2x80x9con streamxe2x80x9d analysis of process fluids, which are performed by analyzers located near the fluid sample source. Sample fluids flow directly from the source to the analyzer through an arrangement of piping and specialty components. This arrangement, referred to as a xe2x80x9csample conditioning systemxe2x80x9d, is configured to extract fluid sample from the source; transport it to the analyzer; and, in the process, condition the fluid so that it is compatible with the analyzer.
Conditioning of the sample fluid by the sample conditioning system may consist of, for example:
(1) filtration to remove unwanted solids or liquids
(2) coalescing to remove aerosol droplets of liquids
(3) heating to prevent condensation of vapor
(4) flow and pressure control and measurement
(5) cooling to lower the sample dew point or remove unwanted liquid vapor.
The sample conditioning system may perform additional functions such as selection of one of several fluid streams for analysis by a single analyzer. This is called xe2x80x9cstream selectionxe2x80x9d or stream multiplexing.
All of the components utilized for extracting, transporting, and conditioning the sample, as described previously, are part of the sample conditioning system. Some sample conditioning systems have components distributed along the entire distance between the source and the analyzer. Typically the largest concentration of these sample conditioning system components are located close together.
Reference to sample conditioning systems in the present invention are designed primarily for utilization in conjunction with closely grouped component arrangements, although the present system does include innovative features which could be useful for more spaced component arrangements. The components as implemented in the sample conditioning system, which are utilized for conditioning sample fluids, will hereinafter be referred to as conditioning components.
Current construction methods for Sample Conditioning System vary little from their first appearance several decades ago. Conditioning components are typically mounted on a vertical panel or shallow enclosure and are interconnected by tubing, piping, and fittings. Heavier conditioning components are mounted to the plate or enclosure with brackets while lighter conditioning components are supported by interconnecting fittings, piping, tubing, etc. Some Sample Conditioning System are further protected by xe2x80x9canalyzer housesxe2x80x9d or shelters which are usually large enough for maintenance technicians to work in and may also house process analyzers. Common to all of the above configurations is the fact that most Sample Conditioning Systems include a uniquely designed and implemented conduit system for conveying the fluid from the sample stream, and through the components, sometimes resulting in a maze of conduits, thereby resulting in high cost, maintenance, and the propensity for leakage from the system.
Several problems arise from the use of current construction methods. Some of the major problems are as follows:
(1) Excessive sizexe2x80x94Sample Conditioning System produced by current construction methods require much spacexe2x80x94a commodity which is very valuable in process areas. In general, lowering the size of analyzer houses or Sample Conditioning System enclosures results in significant cost reduction due to the high cost for space in process areas.
(2) Labor intensivexe2x80x94Configuring, mounting and interconnecting of conditioning components during the construction of a Sample Conditioning System is very labor intensive and therefore costly.
(3) Excessive Sample Conditioning System Internal Fluid Volume and Static Fluid Pocket Volumexe2x80x94It is well known in the industry that large internal volumes and static fluid pocket volume have a negative influence on the performance of Sample Conditioning System. The larger the internal volume and/or static fluid pocket volume in a Sample Conditioning System and the longer it takes to sweep it our after a sample fluid composition change occurs. Therefore Sample Conditioning System with large internal and/static fluid pocket volume require larger amounts of fluid to sweep, resulting in significant inefficiency.
In most cases it is desirable for fluid sample composition arriving at an analyzer to track closely the composition of the sample fluid at its source. In many instances the sample fluid utilized for sweeping cannot be returned to the source and therefore must be wasted. Therefore reducing the internal and static fluid cost related to loss of sample fluid and its environmentally safe disposition. Tube and pipe interconnections between conditioning components contribute the bulk of a Sample Conditioning Systems internal volume. Fittings, especially pipe fittings, introduce static fluid pocket volume to the Sample Conditioning System.
(4) Safety and environmental concernsxe2x80x94It is common for sample fluid leaks to occur in conditioning component tubing and pipe interconnections and as a result of conditioning component failures. Examples of common conditioning component failures are: pressure regulator diaphragm ruptures and valve stem packing shrinkage due to wear or temperature changes. When fluid leaks occur, maintenance technicians can be exposed to toxic materials and fire or explosion hazard. Fluid used for continuously sweeping a Sample Conditioning System presents disposal problems and increases operational expenses.
While the prior art may have contemplated in some degree the utilization of block components having fluid passageways therethrough for fluid conditioning and/or conveyance, said prior art known to the inventor has been limited to hydraulics and other distinguishable configurations and applications.
For example, U.S. Pat. No. 3,831,953, issued 1974 to Leibfritz et al contemplates a xe2x80x9cSolenoid Operated Valve Assemblyxe2x80x9d, teaching a xe2x80x9csealing unit adapted to be clamped between parallel faces of mating valve parts, comprising a sheet-like resilient gasket member engaged with one of said faces, and a uniform thickness plate member engaged with the other of said faces, said gasket member having apertures bounded one side only by lateral rib means which extend beyond the thickness thereof so that said gasket member is squeezed at the rib means between said parallel faces.
While the ""953 device may contemplate a redundant leak isolating system (see col 5, lines 5-28, for example), the system fails to contemplate the overall method and apparatus of the present invention, as pertaining to modular sampling components. The system is clearly designed as valve assembly in a hydraulic system, and as such would not be able to be utilized in the present invention. Other differences between ""953 and the present invention will be made clear in the discussion following infra.
Unlike the prior art, the present invention provides a cost effective, relatively easily implemented, reliable, and efficient system for in-stream sampling, adaptable to a variety of configurations and conditions.
The invention includes a method for:
(a) Constructing a sample fluid conditioning system utilizing modular base and modular conditioning components. This method eliminates tube and pipe interconnections and fittings. This reduces static fluid pocket volume and internal system volume, reduces mounting space requirements, and decreases the time and skill required to construct a sample conditioning system. It also decreases the time required for replacement of failed conditioning components.
(b) Constructing base and conditioning modules. The method further reduces internal and static fluid pocket volume of sample conditioning systems fabricated from modules constructed by this method. This method also provides a means for capturing and transporting to an external disposal system any sample fluids which would otherwise leak to the sample conditioning modules external environment as a result of fluid breaching a fluid barrier or failure of a conditioning component.
(c) Constructing fluid barriers between two surfaces. This method provides a means for leak-free communication of fluids between passageways of adjoining base and conditioning modules and also between passageways of adjoining base modules. This method of constructing fluid barriers also accommodates the capturing of leaks across a primary fluid barrier to prevent fugitive emission of sample fluid. The fluid barriers constructed by this method remain leak free even after thermo-cycling.
(d) Compressing fluid barrier material between two surfaces utilizing strain in a threaded member for supplying the required compressive force. This method compensates for displacement in the seal barrier material which would otherwise reduce the compressive force and permit fluid leaks.
(e) Retaining fluid barrier material utilizing beveled surfaces. This method permits the use of thin plastic or elastic fluid barrier materials and is less susceptible to displacement when thermo-cycled.
(f) Mounting modular base and modular conditioning components in a manner which provides the clamping force required for sealing of fluids.
(g) Attaching fluid transport tube to a base module in a manner that prevents sample fluid leaks to the surrounding environment in the event of a primary fluid barrier failure.
It is therefore an object of the present invention to provide a modular system for in-stream sampling of a fluid in a fluid sampling stream.
It is another object of the present invention to provide an in-stream sampling system which may be utilized in conjunction with a variety of system configurations and requirements, without the need for custom fluid conveyance means, such as piping, conduits or the like.
It is still another object of the present invention to provide a system for in-stream sampling, comprising a modular base member adapted to have situated thereupon, in fluid impermeable fashion, a diverse assortment of communicating fluid conditioning modules.
It is still another object of the present invention to provide a redundant leak sealing means to prevent fugitive emissions.
It is still another object of the present invention to provide an ultra-thin gasket sealing system configured to provide high thermocycling tolerances, and perform satisfactorily in a broad range of temperature extremes.
Lastly, it is an object of the present invention to provide an ultra-thin gasket sealing system configured to provide an effective, low maintenance, high-pressure seal.